chirobob the trick to the acid is to be used be used full strenght on real dirty brick and 50/50 on brick that is average. when you use it at this strength you have to saturate the wall with water,along with fixtures,and windows,once you x jet this formula 2 to 1 onto the wall rinse it off immediately along with windows and fixtures before cleaning the brick.
you have a narrow window of opportunity to wash the brick after this method as the longer it takes you to wash the wall the increased chances of burning the brick,and mortar joints.
yes i made some mistakes when i first started using this formula. but now i know what to do and when to do it.
did i mention i hate porous brick (sponge brick),that is time consuming to wash because you cant get water to dwell on the face.
on regular face brick the faster you can get the solution on and off the wall the faster you can go,with this method there is not the need to blast every single brick which is what i believe most are having to do with the weaker solutions,we also do not use ladders when cleaning houses just a 30 foot and 12 foot extension wand.i can also pull up to a job and be working in 10 minutes with our rig set up,i can roll up as fast too sometimes. we have electric hose reels.
ps this procedure isnt intended for the guys who just got into the business last week,if you did you need to go to the cleaner network and buy your products from steve,as he will show you how to use them and they are safe enough you wont get into trouble with them.